With rapid developments of display technology, a touch panel has gradually gained popularity throughout people's life. The touch panel is divided into three types in accordance with its structure: an add-on mode touch panel, an on-cell mode touch panel and an in-cell mode touch panel. The add-on mode touch panel is a LCD panel with a touch function and comprises a touch screen and a Liquid Crystal Display (LCD) which are produced separately and then bonded together; the add-on mode touch panel has shortcomings such as high production cost, low light transmittance, large thickness and the like. In the in-cell mode touch panel, a touch electrode is embedded inside the LCD so as to reduce the thickness of the touch panel and greatly reduce the production cost; so, the in-cell mode touch panel gradually wins favor of manufacturers.
The in-cell touch panel is provided with a plurality of self-capacitance electrodes insulated from each other. In the case that the touch panel is not touched, a capacitance between the self-capacitance electrode and its adjacent self-capacitance electrode is a capacitance C1 with constant value; and, in the case that the touch panel is touched, the value of the capacitance C1 changes. Coordinates corresponding to respective self-capacitance electrodes are stored in advance in a touch detection chip, and a touch position where the capacitance value changes is determined according to the capacitance value output from signal lines connected to the self-capacitance electrodes.
Referring to FIG. 1, in the in-cell touch panel 10, the self-capacitance electrodes 11 are arranged in an array and each of the self-capacitance electrodes 11 is connected to the touch detection chip 13 through a conductive line 12. Referring to FIG. 2, in the case that the touch panel is touched, digits of the self-capacitance electrodes that are touched represent signal intensity values of the self-capacitance electrodes, and digits of the self-capacitance electrodes that are not touched represent a noise signal; furthermore, in the case that the touch position 14 is located in a center of a region of the adjacent self-capacitance electrodes 11, the capacitance change value of each of the adjacent self-capacitance electrode 11 is small because each self-capacitance electrode 11 at the touch position 14 is uniformly touched. Accordingly, a maximum signal intensity output to the touch detection chip 13 is weak, so that the signal for determining the touch position has a low signal to noise ratio.